Publishers have always emphasized the power of word-of-mouth marketing when it comes to selling books. Booksellers are expected to hand-sell titles to bookstore patrons for this reason, and the shelves are often peppered with "employee recommendation" markers meant to boost interest in specific books.

So it should come as no surprise that this process is increasingly becoming automated.

There have been multiple news reports of publishers getting creative with their recommendation processes over the past few years: In 2014, Penguin created the "Penguin Hotline" for the holidays in which interested customers submitted an online dossier on their gift recipients and soon after received recommendations directly from one of the publisher's employees. Last year, NPR created an online "Book Concierge" that aggregated the titles reviewed by the organization over the course of the year and applied a set of useful filters. And now, HarperCollins has added AI to the equation.